The present invention relates in general to hoistable and lowerable venetian- or pleated blinds, designed and adapted for mounting between the glass panes in double glass pane windows, particularly for multiple glass insulating units. The invention can be utilized for venetian blinds as well as for pleated blinds.
For the sake of simplicity, one shall for the various types of blinds and screens which fall within the scope of the invention, in the following specification including the claims, as general designation for the products involved use the word "blinds", unless a different word is used to designate a particular product.
A number of various proposals for such blinds is known. As illustrative for the prior art, one can refer to U.S. Pat. Nos. 3,292,309, 3,153,819, 2,530,218, 4,459,778 and 3,835,911.
To make various types of blinds designed for mounting between two fixedly mounted glass panes, such as between two panes of glass in an insulating glass unit, offers a number of special problems. Firstly, the available space, in transverse direction, for mounting the blind unit is rather limited, and further, the blind structure must have a rather durable, operationally reliable and maintenance free construction, inasmuch as the blind unit including the system for hoisting and lowering the blind is not readily accessible for repair or replacement, but instead normally will require replacement of the entire glass unit if malfunctions should occur. Furthermore, the blind must be simple and durable in operation by unskilled inhabitants of the building in question.